In radio systems, a radio-frequency (RF) contact is often coupled to circuitry on a substrate having the thickness of an ordinary credit card. In addition, such contacts may require connectors that allow quick connection and disconnection with low insertion loss. Insertion loss results from poor impedance matching between the RF contact and the circuitry. Therefore, a connector providing a good impedance match between an RF contact (e.g., a coaxial cable) and a circuit on a substrate is needed.